Tunable optical device, tunable liquid crystal lens assembly and imaging system using same

Abstract

There is disclosed an imaging system for use in imaging a sample. The imaging system comprising a light source and a light detector. A probe optically coupled to the imaging assembly. The probe being configured to, during use, direct light from the light source to a focal point to illuminate the sample, and from the focal point to the light detector. The probe having a tunable liquid crystal lens (TLCL) assembly comprising at least one pair of TLCLs, the TLCLs of the pair being superposed to one another, a gradient-index (GRIN) lens assembly having a base being optically connected to the TLCL assembly, and a tip opposite to the base. The focal point being at a working distance from the tip. The working distance being adjustable relative to the tip by tuning each TLCL of the TLCL assembly during use.

What is claimed is: 
     
       1. An imaging system for use in imaging a sample comprising:
 an imaging assembly comprising a light source, an objective and a light detector; and 
 a probe optically coupled to the imaging assembly, between the objective and the sample, the probe being configured to, during use, direct light from the light source to a focal point to illuminate the sample, and from the focal point to the light detector, the probe comprising: 
 a tunable liquid crystal lens (TLCL) assembly comprising at least one pair of TLCLs, the TLCLs of the pair being superposed to one another, 
 a gradient-index (GRIN) lens assembly having a base being optically connected to the TLCL assembly, and 
 a tip opposite to the base, the focal point being at a working distance from the tip, the working distance being adjustable relative to the tip by tuning each TLCL of the TLCL assembly during use. 
 
     
     
       2. The imaging system of  claim 1 , wherein one TLCL of the pair is rotated by 180 degrees about an optical axis of the probe with respect to the other TLCL of the pair. 
     
     
       3. The imaging system of  claim 1 , wherein one TLCL of the pair is rotated by 90 degrees about an optical axis of the probe with respect to the other TLCL of the pair. 
     
     
       4. The imaging system of  claim 1 , wherein the probe further comprises a reflector at an end of the GRIN lens assembly opposite the base, the reflector forming an angle relative to an optical axis of the probe such that the adjustable working distance extends away from the optical axis. 
     
     
       5. The imaging system of  claim 1 , wherein each TLCL has two electrodes and a LC layer therebetween, the TLCL being tunable by modifying a frequency of a driving signal provided to across the LC layer via the electrodes. 
     
     
       6. The imaging system of  claim 1 , further comprising a probe module enclosing the imaging assembly, a power source and a communication module such that the imaging system is operable wirelessly as a standalone imaging system. 
     
     
       7. The imaging system of  claim 1 , further comprising a coupling waveguide optically coupling the imaging assembly to the probe. 
     
     
       8. The imaging system of  claim 1 , wherein the at least one TLCL of the TLCL assembly has a nominal diameter of at most 1 mm. 
     
     
       9. The imaging system of  claim 1 , wherein the GRIN lens assembly comprises a GRIN rod optically connected to a focusing GRIN lens. 
     
     
       10. The imaging system of  claim 1 , wherein the imaging system is configured to illuminate the sample with wavelengths corresponding to excitation wavelengths of different molecules of the sample, the molecules emitting a signal upon excitation such that signal is provided to the optical detector. 
     
     
       11. The imaging system of  claim 10 , wherein the probe module further encloses a memory for storing images associated with the sample. 
     
     
       12. The imaging system of  claim 1 , wherein the TLCL assembly comprises two pairs of TLCLs, the TLCLs of the two pairs being superposed to one another, each pair of TLCLs being rotated by 90 degrees from one another about an optical axis of the probe, the two TLCLs of each pair of TLCLs being rotated by 180 degrees from one another about the optical axis of the probe. 
     
     
       13. The imaging system of  claim 12 , wherein the two TLCLs of the each pair are adjacent from one another. 
     
     
       14. The imaging system of  claim 12 , wherein the TLCLs of one pair are interspersed with the TLCLs of the other pair. 
     
     
       15. The imaging system of  claim 1 , wherein the at least one pair of TLCLs of the TLCL assembly have annularly segmented electrodes, the annularly segmented electrodes having a number of electrode segments being independently operable to compensate for aberrations of at least one of the GRIN lens assembly and the sample. 
     
     
       16. The imaging system of  claim 15 , wherein the annularly segmented electrode has at least four electrode segments.